A new milestone has been reached in the field of ultrafast 3D topography measurements. In October, Lyncée Tec SA has delivered to Professor James Friends, Department of Material Sciences and Engineering, University of California San Diego, USA, a DHM T1000 equipped with a Photron Fastcam Nova high speed camera enabling 12’500 3D topography Measurement Per Second (MPS) for a digital resolution of 1024×1024 pixels, and 116’000 MPS for 256×256 pixels.
Professor James Friends, University of California San Diego, USA said: "We needed ultrahigh speed 3D measurements for our research. After considerable exploration we found no solutions available on the market, and we contacted Lyncée to define a suitable solution in close collaboration with their specialists. The novel system was recently delivered and offers an easy-to-use, fully customized software interface with an optical arrangement that matches our needs to adapt the holographic measurement method to high speed cameras. We expect it to enable us to perform outstanding research, and welcome the collaboration with the Lyncée Tec team that is already producing great results."
With their new system, Dr. Friend and his co-workers observe among other non-repeatable random acoustic phenomena on the surface of liquid drops. More generally this achievement opens new application for DHM®, among others in the fields of energy harvesting, impact analysis, fluid interfaces, transients, stress analysis, evaporation, drying, absorption, desorption, and dissolution phenomena, etc. A dedicated software interface has been developed to enable control of the high speed camera parameters (speed, shutter), to handle the different camera trigger modes, to access optimally the camera internal memory buffer, to replay an acquired sequence, to select the relevant frames, and to export them.
Tunable lens recorded with a color video camera at 60 fps VS. high speed DHM at 12800 fps
The high speed DHM is compatible with the Photron range of high speed camera. It can be configured either in transmission or in reflection, and operates at a single wavelength.An application example is the dynamical characterization of the topography of a tunable lens by Optotune AG. The shape of such lenses, and in particular their focal length, can be electrically controlled. The example on the left side of animation is recorded by a color video camera at 60 fps. Camera provides an image through the lens, but not the lens topography. A constant and precise control of the lens shape is nevertheless important to ensure high quality and aberration free performances. DHM enables to measure it with an interferometric resolution.
One interest among others is the dynamical analysis of the shape of the lens when applying a square input voltage.After each voltage change, a ringing effect appears before the lens shape stabilization. The high speed DHM has been used to characterize efficiently this behavior, affecting both the optical properties of the lens and its operating frequency specification range. The animation shows a comparison of the time sequence 3D topography recorded at 60 fps with normal camera and at 12’800 fps with the high speed DHM when driving the lens with a square signal at a frequency of 30Hz.